Metamath Proof Explorer


Theorem ordtype2

Description: For any set-like well-ordered class, if the order isomorphism exists (is a set), then it maps some ordinal onto A isomorphically. Otherwise, F is a proper class, which implies that either ran F C_ A is a proper class or dom F = On . This weak version of ordtype does not require the Axiom of Replacement. (Contributed by Mario Carneiro, 25-Jun-2015)

Ref Expression
Hypothesis oicl.1 F = OrdIso R A
Assertion ordtype2 R We A R Se A F V F Isom E , R dom F A

Proof

Step Hyp Ref Expression
1 oicl.1 F = OrdIso R A
2 eqid recs h V ι v w A | j ran h j R w | u w A | j ran h j R w ¬ u R v = recs h V ι v w A | j ran h j R w | u w A | j ran h j R w ¬ u R v
3 eqid w A | j ran h j R w = w A | j ran h j R w
4 eqid h V ι v w A | j ran h j R w | u w A | j ran h j R w ¬ u R v = h V ι v w A | j ran h j R w | u w A | j ran h j R w ¬ u R v
5 2 3 4 ordtypecbv recs f V ι s y A | i ran f i R y | r y A | i ran f i R y ¬ r R s = recs h V ι v w A | j ran h j R w | u w A | j ran h j R w ¬ u R v
6 eqid x On | t A z recs f V ι s y A | i ran f i R y | r y A | i ran f i R y ¬ r R s x z R t = x On | t A z recs f V ι s y A | i ran f i R y | r y A | i ran f i R y ¬ r R s x z R t
7 simp1 R We A R Se A F V R We A
8 simp2 R We A R Se A F V R Se A
9 simp3 R We A R Se A F V F V
10 5 3 4 6 1 7 8 9 ordtypelem9 R We A R Se A F V F Isom E , R dom F A